Jun 22, 1999

Connexin45, a major connexin of the rabbit sinoatrial node, is co-expressed with connexin43 in a restricted zone at the nodal-crista terminalis border

The Journal of Histochemistry and Cytochemistry : Official Journal of the Histochemistry Society
S R CoppenN J Severs


The pacemaker of the heart, the sinoatrial (SA) node, is characterized by unique electrical coupling properties. To investigate the contribution of gap junction organization and composition to these properties, the spatial pattern of expression of three gap junctional proteins, connexin45 (Cx45), connexin40 (Cx40), and connexin43 (Cx43), was investigated by immunocytochemistry combined with confocal microscopy. The SA nodal regions of rabbits were dissected and rapidly frozen. Serial cryosections were double labeled for Cx45 and Cx43 and for Cx40 and Cx43, using pairs of antibody probes raised in different species. Dual-channel scanning confocal microscopy was applied to allow simultaneous visualization of the different connexins. Cx45 and Cx40, but not Cx43, were expressed in the central SA node. The major part of the SA nodal-crista terminalis border revealed a sharply demarcated boundary between Cx43-expressing myocytes of the crista terminalis and Cx45/Cx40-expressing myocytes of the node. On the endocardial side, however, a transitional zone between the crista terminalis and the periphery of the node was detected in which Cx43 and Cx45 expression merged. These distinct patterns of connexin compartmentation and merger ident...Continue Reading

  • References29
  • Citations62


  • References29
  • Citations62


Mentioned in this Paper

Sinoatrial Node
GJA5 gene
GJA1 gene
GJC1 gene
Muscle Cells
Sinoatrial Block
Gja5 protein, human
GJC1 protein, human

About this Paper

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